A plugin to add an alpha channel to I420 video. Can optionally do chroma keying.

Original commit message from CVS:
* configure.ac:
* gst/alpha/Makefile.am:
* gst/alpha/gstalpha.c: (gst_alpha_method_get_type),
(gst_alpha_get_type), (gst_alpha_base_init),
(gst_alpha_class_init), (gst_alpha_init), (gst_alpha_set_property),
(gst_alpha_get_property), (gst_alpha_sink_link), (gst_alpha_add),
(gst_alpha_chroma_key), (gst_alpha_chain),
(gst_alpha_change_state), (plugin_init):
A plugin to add an alpha channel to I420 video. Can optionally do
chroma keying.
* gst/multipart/Makefile.am:
* gst/multipart/multipart.c: (plugin_init):
* gst/multipart/multipartdemux.c: (gst_multipart_demux_base_init),
(gst_multipart_demux_class_init), (gst_multipart_demux_init),
(gst_multipart_demux_finalize), (gst_multipart_demux_handle_event),
(gst_multipart_find_pad_by_mime), (gst_multipart_demux_chain),
(gst_multipart_demux_change_state),
(gst_multipart_demux_plugin_init):
* gst/multipart/multipartmux.c: (gst_multipart_mux_get_type),
(gst_multipart_mux_base_init), (gst_multipart_mux_class_init),
(gst_multipart_mux_get_sink_event_masks), (gst_multipart_mux_init),
(gst_multipart_mux_sinkconnect), (gst_multipart_mux_pad_link),
(gst_multipart_mux_pad_unlink),
(gst_multipart_mux_request_new_pad),
(gst_multipart_mux_handle_src_event),
(gst_multipart_mux_next_buffer), (gst_multipart_mux_compare_pads),
(gst_multipart_mux_queue_pads), (gst_multipart_mux_loop),
(gst_multipart_mux_get_property), (gst_multipart_mux_set_property),
(gst_multipart_mux_change_state), (gst_multipart_mux_plugin_init):
A Multipart demuxer/muxer. Not sure if it violates specs. Used to
send multipart jpeg images to a browser.
* gst/videobox/Makefile.am:
* gst/videobox/README:
* gst/videobox/gstvideobox.c: (gst_video_box_fill_get_type),
(gst_video_box_get_type), (gst_video_box_base_init),
(gst_video_box_class_init), (gst_video_box_init),
(gst_video_box_set_property), (gst_video_box_get_property),
(gst_video_box_sink_link), (gst_video_box_i420),
(gst_video_box_ayuv), (gst_video_box_chain),
(gst_video_box_change_state), (plugin_init):
Crops or adds borders around an image. can do alpha channel
borders as well.
* gst/videomixer/Makefile.am:
* gst/videomixer/README:
* gst/videomixer/videomixer.c: (gst_videomixer_pad_get_type),
(gst_videomixer_pad_base_init), (gst_videomixer_pad_class_init),
(gst_videomixer_pad_get_sink_event_masks),
(gst_videomixer_pad_get_property),
(gst_videomixer_pad_set_property),
(gst_videomixer_pad_sinkconnect), (gst_videomixer_pad_link),
(gst_videomixer_pad_unlink), (gst_videomixer_pad_init),
(gst_video_mixer_background_get_type), (gst_videomixer_get_type),
(gst_videomixer_base_init), (gst_videomixer_class_init),
(gst_videomixer_init), (gst_videomixer_request_new_pad),
(gst_videomixer_handle_src_event),
(gst_videomixer_blend_ayuv_i420), (gst_videomixer_fill_checker),
(gst_videomixer_fill_color), (gst_videomixer_fill_queues),
(gst_videomixer_blend_buffers), (gst_videomixer_update_queues),
(gst_videomixer_loop), (gst_videomixer_get_property),
(gst_videomixer_set_property), (gst_videomixer_change_state),
(plugin_init):
Generic video mixer plugin, can handle multiple inputs all with
different framerates and video sizes. Is fully alpha channel
aware.

3 files changed, 764 insertions, 0 deletions

diff --git a/gst/videobox/Makefile.am b/gst/videobox/Makefile.am
new file mode 100644
index 00000000..37da9aae
--- /dev/null
+++ b/gst/videobox/Makefile.am
@@ -0,0 +1,9 @@
+
+plugin_LTLIBRARIES = libgstvideobox.la
+
+libgstvideobox_la_SOURCES = gstvideobox.c
+libgstvideobox_la_CFLAGS = $(GST_CFLAGS)
+libgstvideobox_la_LIBADD =
+libgstvideobox_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+
+noinst_HEADERS = 
diff --git a/gst/videobox/README b/gst/videobox/README
new file mode 100644
index 00000000..e71da590
--- /dev/null
+++ b/gst/videobox/README
@@ -0,0 +1,21 @@
+Videobox
+--------
+
+This plugin crops or enlarges the image. It takes 4 values as input, a
+top, bottom, left and right offset. Positive values will crop that much
+pixels from the respective border of the image, negative values will add
+that much pixels. When pixels are added, you can specify their color. 
+Some predefined colors are usable with an enum property.
+
+The plugin is alpha channel aware and will try to negotiate with a format
+that supports alpha channels first. When alpha channel is active two
+other properties, alpha and border_alpha can be used to set the alpha
+values of the inner picture and the border respectively. an alpha value of
+0.0 means total transparency, 1.0 is opaque.
+
+The videobox plugin has many uses such as doing a mosaic of pictures, 
+letterboxing video, cutting out pieces of video, picture in picture, etc..
+
+TODO
+
+- add enum to specify common aspect ratios/sizes and add borders/crop
diff --git a/gst/videobox/gstvideobox.c b/gst/videobox/gstvideobox.c
new file mode 100644
index 00000000..c1d9c3ba
--- /dev/null
+++ b/gst/videobox/gstvideobox.c
@@ -0,0 +1,734 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include <gst/gst.h>
+#include <gst/video/video.h>
+
+#include <string.h>
+
+#define GST_TYPE_VIDEO_BOX \
+  (gst_video_box_get_type())
+#define GST_VIDEO_BOX(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_VIDEO_BOX,GstVideoBox))
+#define GST_VIDEO_BOX_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_VIDEO_BOX,GstVideoBoxClass))
+#define GST_IS_VIDEO_BOX(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_VIDEO_BOX))
+#define GST_IS_VIDEO_BOX_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_VIDEO_BOX))
+
+typedef struct _GstVideoBox GstVideoBox;
+typedef struct _GstVideoBoxClass GstVideoBoxClass;
+
+typedef enum
+{
+  VIDEO_BOX_FILL_BLACK,
+  VIDEO_BOX_FILL_GREEN,
+  VIDEO_BOX_FILL_BLUE,
+}
+GstVideoBoxFill;
+
+struct _GstVideoBox
+{
+  GstElement element;
+
+  /* pads */
+  GstPad *sinkpad;
+  GstPad *srcpad;
+
+  /* caps */
+  gint in_width, in_height;
+  gint out_width, out_height;
+
+  gint box_left, box_right, box_top, box_bottom;
+
+  gint border_left, border_right, border_top, border_bottom;
+  gint crop_left, crop_right, crop_top, crop_bottom;
+
+  gboolean use_alpha;
+  gdouble alpha;
+  gdouble border_alpha;
+
+  GstVideoBoxFill fill_type;
+};
+
+struct _GstVideoBoxClass
+{
+  GstElementClass parent_class;
+};
+
+/* elementfactory information */
+static GstElementDetails gst_video_box_details =
+GST_ELEMENT_DETAILS ("video box filter",
+    "Filter/Effect/Video",
+    "Resizes a video by adding borders or cropping",
+    "Wim Taymans <wim@fluendo.com>");
+
+
+/* VideoBox signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+#define DEFAULT_LEFT      0
+#define DEFAULT_RIGHT     0
+#define DEFAULT_TOP       0
+#define DEFAULT_BOTTOM    0
+#define DEFAULT_FILL_TYPE VIDEO_BOX_FILL_BLACK
+#define DEFAULT_ALPHA     1.0
+#define DEFAULT_BORDER_ALPHA 1.0
+
+enum
+{
+  ARG_0,
+  ARG_LEFT,
+  ARG_RIGHT,
+  ARG_TOP,
+  ARG_BOTTOM,
+  ARG_FILL_TYPE,
+  ARG_ALPHA,
+  ARG_BORDER_ALPHA,
+  /* FILL ME */
+};
+
+static GstStaticPadTemplate gst_video_box_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("{ I420, AYUV }"))
+    );
+
+static GstStaticPadTemplate gst_video_box_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("I420"))
+    );
+
+
+static void gst_video_box_base_init (gpointer g_class);
+static void gst_video_box_class_init (GstVideoBoxClass * klass);
+static void gst_video_box_init (GstVideoBox * video_box);
+
+static void gst_video_box_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_video_box_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static GstPadLinkReturn
+gst_video_box_sink_link (GstPad * pad, const GstCaps * caps);
+static void gst_video_box_chain (GstPad * pad, GstData * _data);
+
+static GstElementStateReturn gst_video_box_change_state (GstElement * element);
+
+
+static GstElementClass *parent_class = NULL;
+
+#define GST_TYPE_VIDEO_BOX_FILL (gst_video_box_fill_get_type())
+static GType
+gst_video_box_fill_get_type (void)
+{
+  static GType video_box_fill_type = 0;
+  static GEnumValue video_box_fill[] = {
+    {VIDEO_BOX_FILL_BLACK, "0", "Black"},
+    {VIDEO_BOX_FILL_GREEN, "1", "Colorkey green"},
+    {VIDEO_BOX_FILL_BLUE, "2", "Colorkey blue"},
+    {0, NULL, NULL},
+  };
+
+  if (!video_box_fill_type) {
+    video_box_fill_type =
+        g_enum_register_static ("GstVideoBoxFill", video_box_fill);
+  }
+  return video_box_fill_type;
+}
+
+/* static guint gst_video_box_signals[LAST_SIGNAL] = { 0 }; */
+
+GType
+gst_video_box_get_type (void)
+{
+  static GType video_box_type = 0;
+
+  if (!video_box_type) {
+    static const GTypeInfo video_box_info = {
+      sizeof (GstVideoBoxClass),
+      gst_video_box_base_init,
+      NULL,
+      (GClassInitFunc) gst_video_box_class_init,
+      NULL,
+      NULL,
+      sizeof (GstVideoBox),
+      0,
+      (GInstanceInitFunc) gst_video_box_init,
+    };
+
+    video_box_type =
+        g_type_register_static (GST_TYPE_ELEMENT, "GstVideoBox",
+        &video_box_info, 0);
+  }
+  return video_box_type;
+}
+
+static void
+gst_video_box_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details (element_class, &gst_video_box_details);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_video_box_sink_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_video_box_src_template));
+}
+static void
+gst_video_box_class_init (GstVideoBoxClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
+
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FILL_TYPE,
+      g_param_spec_enum ("fill", "Fill", "How to fill the borders",
+          GST_TYPE_VIDEO_BOX_FILL, DEFAULT_FILL_TYPE,
+          (GParamFlags) G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_LEFT,
+      g_param_spec_int ("left", "Left", "Pixels to box at left",
+          G_MININT, G_MAXINT, DEFAULT_LEFT, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_RIGHT,
+      g_param_spec_int ("right", "Right", "Pixels to box at right",
+          G_MININT, G_MAXINT, DEFAULT_RIGHT, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TOP,
+      g_param_spec_int ("top", "Top", "Pixels to box at top",
+          G_MININT, G_MAXINT, DEFAULT_TOP, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_BOTTOM,
+      g_param_spec_int ("bottom", "Bottom", "Pixels to box at bottom",
+          G_MININT, G_MAXINT, DEFAULT_BOTTOM, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ALPHA,
+      g_param_spec_double ("alpha", "Alpha", "Alpha value picture",
+          0.0, 1.0, DEFAULT_ALPHA, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_BORDER_ALPHA,
+      g_param_spec_double ("border_alpha", "Border Alpha",
+          "Alpha value of the border", 0.0, 1.0, DEFAULT_BORDER_ALPHA,
+          G_PARAM_READWRITE));
+
+  gobject_class->set_property = gst_video_box_set_property;
+  gobject_class->get_property = gst_video_box_get_property;
+
+  gstelement_class->change_state = gst_video_box_change_state;
+}
+
+static void
+gst_video_box_init (GstVideoBox * video_box)
+{
+  /* create the sink and src pads */
+  video_box->sinkpad =
+      gst_pad_new_from_template (gst_static_pad_template_get
+      (&gst_video_box_sink_template), "sink");
+  gst_element_add_pad (GST_ELEMENT (video_box), video_box->sinkpad);
+  gst_pad_set_chain_function (video_box->sinkpad, gst_video_box_chain);
+  gst_pad_set_link_function (video_box->sinkpad, gst_video_box_sink_link);
+
+  video_box->srcpad =
+      gst_pad_new_from_template (gst_static_pad_template_get
+      (&gst_video_box_src_template), "src");
+  gst_element_add_pad (GST_ELEMENT (video_box), video_box->srcpad);
+
+  video_box->box_right = DEFAULT_RIGHT;
+  video_box->box_left = DEFAULT_LEFT;
+  video_box->box_top = DEFAULT_TOP;
+  video_box->box_bottom = DEFAULT_BOTTOM;
+  video_box->fill_type = DEFAULT_FILL_TYPE;
+  video_box->alpha = DEFAULT_ALPHA;
+  video_box->border_alpha = DEFAULT_BORDER_ALPHA;
+
+  GST_FLAG_SET (video_box, GST_ELEMENT_EVENT_AWARE);
+}
+
+/* do we need this function? */
+static void
+gst_video_box_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstVideoBox *video_box;
+
+  /* it's not null if we got it, but it might not be ours */
+  g_return_if_fail (GST_IS_VIDEO_BOX (object));
+
+  video_box = GST_VIDEO_BOX (object);
+
+  switch (prop_id) {
+    case ARG_LEFT:
+      video_box->box_left = g_value_get_int (value);
+      if (video_box->box_left < 0) {
+        video_box->border_left = -video_box->box_left;
+        video_box->crop_left = 0;
+      } else {
+        video_box->border_left = 0;
+        video_box->crop_left = video_box->box_left;
+      }
+      break;
+    case ARG_RIGHT:
+      video_box->box_right = g_value_get_int (value);
+      if (video_box->box_right < 0) {
+        video_box->border_right = -video_box->box_right;
+        video_box->crop_right = 0;
+      } else {
+        video_box->border_right = 0;
+        video_box->crop_right = video_box->box_right;
+      }
+      break;
+    case ARG_TOP:
+      video_box->box_top = g_value_get_int (value);
+      if (video_box->box_top < 0) {
+        video_box->border_top = -video_box->box_top;
+        video_box->crop_top = 0;
+      } else {
+        video_box->border_top = 0;
+        video_box->crop_top = video_box->box_top;
+      }
+      break;
+    case ARG_BOTTOM:
+      video_box->box_bottom = g_value_get_int (value);
+      if (video_box->box_bottom < 0) {
+        video_box->border_bottom = -video_box->box_bottom;
+        video_box->crop_bottom = 0;
+      } else {
+        video_box->border_bottom = 0;
+        video_box->crop_bottom = video_box->box_bottom;
+      }
+      break;
+    case ARG_FILL_TYPE:
+      video_box->fill_type = g_value_get_enum (value);
+      break;
+    case ARG_ALPHA:
+      video_box->alpha = g_value_get_double (value);
+      break;
+    case ARG_BORDER_ALPHA:
+      video_box->border_alpha = g_value_get_double (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+static void
+gst_video_box_get_property (GObject * object, guint prop_id, GValue * value,
+    GParamSpec * pspec)
+{
+  GstVideoBox *video_box;
+
+  /* it's not null if we got it, but it might not be ours */
+  g_return_if_fail (GST_IS_VIDEO_BOX (object));
+
+  video_box = GST_VIDEO_BOX (object);
+
+  switch (prop_id) {
+    case ARG_LEFT:
+      g_value_set_int (value, video_box->box_left);
+      break;
+    case ARG_RIGHT:
+      g_value_set_int (value, video_box->box_right);
+      break;
+    case ARG_TOP:
+      g_value_set_int (value, video_box->box_top);
+      break;
+    case ARG_BOTTOM:
+      g_value_set_int (value, video_box->box_bottom);
+      break;
+    case ARG_FILL_TYPE:
+      g_value_set_enum (value, video_box->fill_type);
+      break;
+    case ARG_ALPHA:
+      g_value_set_double (value, video_box->alpha);
+      break;
+    case ARG_BORDER_ALPHA:
+      g_value_set_double (value, video_box->border_alpha);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static GstPadLinkReturn
+gst_video_box_sink_link (GstPad * pad, const GstCaps * caps)
+{
+  GstVideoBox *video_box;
+  GstStructure *structure;
+  gboolean ret;
+
+  video_box = GST_VIDEO_BOX (gst_pad_get_parent (pad));
+  structure = gst_caps_get_structure (caps, 0);
+
+  ret = gst_structure_get_int (structure, "width", &video_box->in_width);
+  ret &= gst_structure_get_int (structure, "height", &video_box->in_height);
+
+  return GST_PAD_LINK_OK;
+}
+
+#define GST_VIDEO_I420_Y_OFFSET(width,height) (0)
+#define GST_VIDEO_I420_U_OFFSET(width,height) ((width)*(height))
+#define GST_VIDEO_I420_V_OFFSET(width,height) ((width)*(height) + ((width/2)*(height/2)))
+
+#define GST_VIDEO_I420_Y_ROWSTRIDE(width) (width)
+#define GST_VIDEO_I420_U_ROWSTRIDE(width) ((width)/2)
+#define GST_VIDEO_I420_V_ROWSTRIDE(width) ((width)/2)
+
+static int yuv_colors_Y[] = { 16, 150, 29 };
+static int yuv_colors_U[] = { 128, 46, 255 };
+static int yuv_colors_V[] = { 128, 21, 107 };
+
+static void
+gst_video_box_i420 (GstVideoBox * video_box, guint8 * src, guint8 * dest)
+{
+  guint8 *srcY, *srcU, *srcV;
+  guint8 *destY, *destU, *destV;
+  gint crop_width, crop_height;
+  gint out_width, out_height;
+  gint src_stride;
+  gint br, bl, bt, bb;
+  gint j;
+  gint color1, color2;
+
+  br = video_box->border_right;
+  bl = video_box->border_left;
+  bt = video_box->border_top;
+  bb = video_box->border_bottom;
+
+  out_width = video_box->out_width;
+  out_height = video_box->out_height;
+
+  destY = dest + GST_VIDEO_I420_Y_OFFSET (out_width, out_height);
+
+  srcY =
+      src + GST_VIDEO_I420_Y_OFFSET (video_box->in_width, video_box->in_height);
+  src_stride = GST_VIDEO_I420_Y_ROWSTRIDE (video_box->in_width);
+
+  crop_width =
+      video_box->in_width - (video_box->crop_left + video_box->crop_right);
+  crop_height =
+      video_box->in_height - (video_box->crop_top + video_box->crop_bottom);
+
+  srcY += src_stride * video_box->crop_top + video_box->crop_left;
+
+  color1 = yuv_colors_Y[video_box->fill_type];
+
+  /* copy Y plane first */
+  for (j = 0; j < bt; j++) {
+    memset (destY, color1, out_width);
+    destY += out_width;
+  }
+  for (j = 0; j < crop_height; j++) {
+    memset (destY, color1, bl);
+    destY += bl;
+    memcpy (destY, srcY, crop_width);
+    destY += crop_width;
+    memset (destY, color1, br);
+    destY += br;
+    srcY += src_stride;
+  }
+  for (j = 0; j < bb; j++) {
+    memset (destY, color1, out_width);
+    destY += out_width;
+  }
+
+  src_stride = GST_VIDEO_I420_U_ROWSTRIDE (video_box->in_width);
+
+  destU = dest + GST_VIDEO_I420_U_OFFSET (out_width, out_height);
+  destV = dest + GST_VIDEO_I420_V_OFFSET (out_width, out_height);
+
+  crop_width /= 2;
+  crop_height /= 2;
+  out_width /= 2;
+  out_height /= 2;
+  bb /= 2;
+  bt /= 2;
+  br /= 2;
+  bl /= 2;
+
+  srcU =
+      src + GST_VIDEO_I420_U_OFFSET (video_box->in_width, video_box->in_height);
+  srcV =
+      src + GST_VIDEO_I420_V_OFFSET (video_box->in_width, video_box->in_height);
+  srcU += src_stride * (video_box->crop_top / 2) + (video_box->crop_left / 2);
+  srcV += src_stride * (video_box->crop_top / 2) + (video_box->crop_left / 2);
+
+  color1 = yuv_colors_U[video_box->fill_type];
+  color2 = yuv_colors_V[video_box->fill_type];
+
+  for (j = 0; j < bt; j++) {
+    memset (destU, color1, out_width);
+    memset (destV, color2, out_width);
+    destU += out_width;
+    destV += out_width;
+  }
+  for (j = 0; j < crop_height; j++) {
+    memset (destU, color1, bl);
+    destU += bl;
+    /* copy U plane */
+    memcpy (destU, srcU, crop_width);
+    destU += crop_width;
+    memset (destU, color1, br);
+    destU += br;
+    srcU += src_stride;
+
+    memset (destV, color2, bl);
+    destV += bl;
+    /* copy V plane */
+    memcpy (destV, srcV, crop_width);
+    destV += crop_width;
+    memset (destV, color2, br);
+    destV += br;
+    srcV += src_stride;
+  }
+  for (j = 0; j < bb; j++) {
+    memset (destU, color1, out_width);
+    memset (destV, color2, out_width);
+    destU += out_width;
+    destV += out_width;
+  }
+}
+
+static void
+gst_video_box_ayuv (GstVideoBox * video_box, guint8 * src, guint8 * dest)
+{
+  guint8 *srcY, *srcU, *srcV;
+  gint crop_width, crop_width2, crop_height;
+  gint out_width, out_height;
+  gint src_stride, src_stride2;
+  gint br, bl, bt, bb;
+  gint colorY, colorU, colorV;
+  gint i, j;
+  guint8 b_alpha = (guint8) (video_box->border_alpha * 255);
+  guint8 i_alpha = (guint8) (video_box->alpha * 255);
+  guint32 *destp = (guint32 *) dest;
+  guint32 ayuv;
+
+  br = video_box->border_right;
+  bl = video_box->border_left;
+  bt = video_box->border_top;
+  bb = video_box->border_bottom;
+
+  out_width = video_box->out_width;
+  out_height = video_box->out_height;
+
+  src_stride = GST_VIDEO_I420_Y_ROWSTRIDE (video_box->in_width);
+  src_stride2 = src_stride / 2;
+
+  crop_width =
+      video_box->in_width - (video_box->crop_left + video_box->crop_right);
+  crop_width2 = crop_width / 2;
+  crop_height =
+      video_box->in_height - (video_box->crop_top + video_box->crop_bottom);
+
+  srcY =
+      src + GST_VIDEO_I420_Y_OFFSET (video_box->in_width, video_box->in_height);
+  srcY += src_stride * video_box->crop_top + video_box->crop_left;
+  srcU =
+      src + GST_VIDEO_I420_U_OFFSET (video_box->in_width, video_box->in_height);
+  srcU += src_stride2 * (video_box->crop_top / 2) + (video_box->crop_left / 2);
+  srcV =
+      src + GST_VIDEO_I420_V_OFFSET (video_box->in_width, video_box->in_height);
+  srcV += src_stride2 * (video_box->crop_top / 2) + (video_box->crop_left / 2);
+
+  colorY = yuv_colors_Y[video_box->fill_type];
+  colorU = yuv_colors_U[video_box->fill_type];
+  colorV = yuv_colors_V[video_box->fill_type];
+
+  ayuv =
+      GUINT32_FROM_BE ((b_alpha << 24) | (colorY << 16) | (colorU << 8) |
+      colorV);
+
+  /* top border */
+  for (i = 0; i < bt; i++) {
+    for (j = 0; j < out_width; j++) {
+      *destp++ = ayuv;
+    }
+  }
+  for (i = 0; i < crop_height; i++) {
+    /* left border */
+    for (j = 0; j < bl; j++) {
+      *destp++ = ayuv;
+    }
+    dest = (guint8 *) destp;
+    /* center */
+    for (j = 0; j < crop_width2; j++) {
+      *dest++ = i_alpha;
+      *dest++ = *srcY++;
+      *dest++ = *srcU;
+      *dest++ = *srcV;
+      *dest++ = i_alpha;
+      *dest++ = *srcY++;
+      *dest++ = *srcU++;
+      *dest++ = *srcV++;
+    }
+    if (i % 2 == 0) {
+      srcU -= crop_width2;
+      srcV -= crop_width2;
+    } else {
+      srcU += src_stride2 - crop_width2;
+      srcV += src_stride2 - crop_width2;
+    }
+    srcY += src_stride - crop_width;
+
+    destp = (guint32 *) dest;
+    /* right border */
+    for (j = 0; j < br; j++) {
+      *destp++ = ayuv;
+    }
+  }
+  /* bottom border */
+  for (i = 0; i < bb; i++) {
+    for (j = 0; j < out_width; j++) {
+      *destp++ = ayuv;
+    }
+  }
+}
+
+static void
+gst_video_box_chain (GstPad * pad, GstData * _data)
+{
+  GstBuffer *buffer;
+  GstVideoBox *video_box;
+  GstBuffer *outbuf;
+  gint new_width, new_height;
+
+  video_box = GST_VIDEO_BOX (gst_pad_get_parent (pad));
+
+  if (GST_IS_EVENT (_data)) {
+    GstEvent *event = GST_EVENT (_data);
+
+    switch (GST_EVENT_TYPE (event)) {
+      default:
+        gst_pad_event_default (pad, event);
+        break;
+    }
+    return;
+  }
+
+  buffer = GST_BUFFER (_data);
+
+  new_width =
+      video_box->in_width - (video_box->box_left + video_box->box_right);
+  new_height =
+      video_box->in_height - (video_box->box_top + video_box->box_bottom);
+
+  if (new_width != video_box->out_width ||
+      new_height != video_box->out_height ||
+      !GST_PAD_CAPS (video_box->srcpad)) {
+    GstCaps *newcaps;
+
+    newcaps = gst_caps_copy (gst_pad_get_negotiated_caps (video_box->sinkpad));
+
+    video_box->use_alpha = TRUE;
+
+    /* try AYUV first */
+    gst_caps_set_simple (newcaps,
+        "format", GST_TYPE_FOURCC, GST_STR_FOURCC ("AYUV"),
+        "width", G_TYPE_INT, new_width, "height", G_TYPE_INT, new_height, NULL);
+
+    if (GST_PAD_LINK_FAILED (gst_pad_try_set_caps (video_box->srcpad, newcaps))) {
+      video_box->use_alpha = FALSE;
+      newcaps =
+          gst_caps_copy (gst_pad_get_negotiated_caps (video_box->sinkpad));
+      gst_caps_set_simple (newcaps, "format", GST_TYPE_FOURCC,
+          GST_STR_FOURCC ("I420"), "width", G_TYPE_INT, new_width, "height",
+          G_TYPE_INT, new_height, NULL);
+
+      if (GST_PAD_LINK_FAILED (gst_pad_try_set_caps (video_box->srcpad,
+                  newcaps))) {
+        GST_ELEMENT_ERROR (video_box, CORE, NEGOTIATION, (NULL), (NULL));
+        return;
+      }
+    }
+
+    video_box->out_width = new_width;
+    video_box->out_height = new_height;
+  }
+
+  if (video_box->use_alpha) {
+    outbuf = gst_buffer_new_and_alloc (new_width * new_height * 4);
+
+    gst_video_box_ayuv (video_box,
+        GST_BUFFER_DATA (buffer), GST_BUFFER_DATA (outbuf));
+  } else {
+    outbuf = gst_buffer_new_and_alloc ((new_width * new_height * 3) / 2);
+
+    gst_video_box_i420 (video_box,
+        GST_BUFFER_DATA (buffer), GST_BUFFER_DATA (outbuf));
+  }
+  GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (buffer);
+  GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buffer);
+
+
+  gst_buffer_unref (buffer);
+
+  gst_pad_push (video_box->srcpad, GST_DATA (outbuf));
+}
+
+static GstElementStateReturn
+gst_video_box_change_state (GstElement * element)
+{
+  GstVideoBox *video_box;
+
+  video_box = GST_VIDEO_BOX (element);
+
+  switch (GST_STATE_TRANSITION (element)) {
+    case GST_STATE_NULL_TO_READY:
+      break;
+    case GST_STATE_READY_TO_PAUSED:
+      break;
+    case GST_STATE_PAUSED_TO_PLAYING:
+      break;
+    case GST_STATE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_PAUSED_TO_READY:
+      break;
+    case GST_STATE_READY_TO_NULL:
+      break;
+  }
+
+  parent_class->change_state (element);
+
+  return GST_STATE_SUCCESS;
+}
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "videobox", GST_RANK_NONE,
+      GST_TYPE_VIDEO_BOX);
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "videobox",
+    "resizes a video by adding borders or cropping",
+    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)